180 likes | 369 Vues
Pipe system life time cost. Energy will be increasingly precious Environment focus will grow The pipe system is expensive Life time expectancy is over 30 Years. What is life time cost ?. Investment cost Pipe material Pipe installation Excavation and restoration Inspection
E N D
Pipe system life time cost • Energy will be increasingly precious • Environment focus will grow • The pipe system is expensive • Life time expectancy is over 30 Years
What is life time cost ? • Investment cost • Pipe material • Pipe installation • Excavation and restoration • Inspection • Operation cost • Pumping • Heat loss • Maintenance cost • Repairs • Management
The Calculation Example • The model system supplies 10 MW • Flow 90OC and return 50OC • The pipe system is: • 2 x 1000 m. DN 250 • 2 x 1500 m. DN 80 • 100 consumer connections a´100 kW 2 x 2500 m. DN 32 • 100 consumer connections a´10kW 2 x 2000 m. 18 mm. Cu-flex
Investment costThump rules • Pipes 380 000 EUR • Insulation series 2 + 12% • Double Pipes + 25% • X-linked shrink joints +5% • Pipe installation 50% of pipes • Inspection 0- 50 000 EUR • Excavation 100% of pipes • Series 2 + 15% • Double – 20% • Asphalting 50% of pipes
Heat conductivity l lPUR = lSOLID +lRADIATION +lGAS • lSOLID is not changing over time • lRADIATION is not changing over time • lGAS varies with the diffusion • lSOLID +lRADIATION app. 6 – 12 mW/mK depending upon the cell structure
The gas composition • The gas is Cyklopentane, CO2 and air • Cyklopentane, CP 40% • Carbon dioxide, CO2 55% • Air ( N2 + O2 )5%
Lambda gas • Cyklopentane: 0,012 W/mK • Carbon dioxide: 0,017 W/mK • Air: 0,027 W/mK
Lambda values new Logstor pipes • Conti pipes: 0.024 W/mK • Traditional pipes: 0,0275 W/mK • Flex pipes: 0,025 W/mK
German failurestatistic 2000 5
Swedish failure statistics 1998-2001 5
Failure rates • With simple and cheap joints Joint failures may be > 0,5 failure/km./year • With PEX shrink joints or weld joints joint failures are < 0,05 failure/km./year • With low inspection rates Weld seam failures may be > 0,2 failure/km./year • With proper inspection Weld seam failures may be < 0,02 failure/km./year
Failure costs • The repair cost for a simple failure is estimated 3 000 EUR • The example: • With cheap joints, repair cost is 20 000 EUR / year • With PEX- and weld joints, it is < 2 000 EUR / year • With low inspection, weld repair cost is 10 000 EUR / year • With proper inspection, it is 1 000 EUR / year • Do it cheap and easy and you have high repair costs • Do it right and you have low repair costs
Life time costs The following picture compares: “Series 1 cheap”: • DN 25, DN 32, DN 80, DN 250 all traditional without barrier, cheap joints and low inspection level. “Series 1 barrier”: • 18 Cu-flex, DN 32, DN 80, DN 250 Conti pipes with barrier, PEX joints and proper inspection Series 2 barrier: • 18 Cu-flex, DN 32, DN 80, DN 250 Conti pipes with barrier, PEX joints and proper inspection Double pipes: • 18 Cu-flex, DN 32, DN 80, all double and DN 250 Conti pipes with barrier, PEX joints and proper inspection Const. Flow: • is Series 1 cheap with constant flow pumps
Life time costs kEUR Present values
Life time cost Calculation settings: • Pumping energy 1% of total heat supply • Constant flow pumps 3% of total heat supply • Heat price 0,025 EUR/kWh • Power price 0,06 EUR/kWh • All amounts as present value over 20 years • Inflation 2% • Energy price rise 2% • Bank interest 6%
The lessons are: • Do not save on inspection • Do not accept “cheap” joints • Keep your heat loss down • Use flow controlled pumps